Improvement of mouth functional disability in systemic sclerosis patients over one year in a trial of fat transplantation versus adipose-derived stromal cells

Background. Systemic sclerosis (SSc) is a multisystem disease characterized by cutaneous and visceral fibrosis. Face and mouth changes include telangiectasia, sicca syndrome, and thinning and reduction of mouth width (microcheilia) and opening (microstomia). We applied autologous fat transplantation compared with autologous adipose-derived stromal cells (ADSCs) injection to evaluate the clinical improvement of mouth opening. Methods. From February to May 2013 ten consecutive SSc patients were enrolled from the outpatient clinic of Plastic Surgery Department of Sapienza University of Rome. Patients were divided into two groups as follows: 5 patients were treated with fat transplantation and 5 patients received infiltration of ADSCs produced by cell factory of our institution. To value mouth opening, we use the Italian version of Mouth Handicap in Systemic Sclerosis Scale (IvMHISS). Mouth opening was assessed in centimetres (Maximal Mouth Opening, MMO). In order to evaluate compliance and physician and patient satisfaction, we employed a Questionnaire of Satisfaction and the Visual Analogic Scale (VAS) performed before starting study and 1 year after the last treatment. Results and Conclusion. We noticed that both procedures obtained significant results but neither one emerged as a first-choice technique. The present clinical experimentation should be regarded as a starting point for further experimental research and clinical trials

Attachment anxiety and depressive symptoms in undergraduate medical students

Introduction Several studies report that medical students are at high risk of depression. Despite the variability in students’ vulnerability to depression, the role of individual differences in depression risk among medical students has hardly been investigated. Studies outside of medical student populations have shown that individual differences in attachment style and emotion regulation participate in vulnerability to depression. Objectives This study investigates to what extent medical students’ depressive symptoms are related to differences in students’ insecure attachment styles and their perception of reduced access to emotion regulation strategies. Methods In a cross-sectional quantitative study, undergraduate medical students at the beginning of their second academic year completed online questionnaires measuring their attachment style, difficulties in emotion regulation, and depressive symptoms. Results Out of the 390 medical students invited, 267 participated in the survey. Higher secure attachment was associated with fewer depressive symptoms. Medical students’ insecure attachment style and emotion dysregulation were significantly related to depressive symptoms. Difficulties in employing strategies to disengage from one’s own negative affect partly mediated the effects of two dimensions of insecure anxious attachment—need for approval and preoccupation with relationships—on depressive symptoms. Discussion Anxious attachment style and limited access to emotion regulation strategies participate in medical students’ depressive symptoms. These findings highlight the need for acknowledging medical students’ attachment style and students’ perceived access to emotion regulation strategies for the early identification of and intervention programs for the risk of depression

Experimental validation of topology optimization of Additive Manufactured polymeric beams subjected to three-point bending test

Topology Optimization (TO) is a powerful tool for the optimization of product geometry and weight for compliance with structural requirements. The shapes generated by TO are generally complex and intricated, but nowadays they can be produced by Additive Manufacturing (AM) or 3D Printing. 3D Printing is the term that is widely used to address layered manufacturing in the case of consumer applications with polymeric materials, while AM mostly refers to industrial applications. The basic algorithm for TO is based on the Solid Isotropic Material with Penalisation (SIMP) method. The increasing importance of AM has recently driven researchers to develop modified versions of the SIMP algorithm for considering the constraints and peculiarities of layered manufacturing, such as the use of lattice structures with intermediate densities or the need to include support structures in the case of overhanging features. Owing to the diffusion of AM and 3D Printing, SIMP methods have also been implemented in many commercial computer aided design and engineering (CAD/CAE) software packages. Specific TO software is also available outside CAD packages. However, the anisotropic nature of layered technologies brings additional challenges for TO methods, especially in the case of load bearing structures. There is the need of improving the performances and the accuracy of TO by considering the peculiarities of the adopted AM techniques and the properties of the specific material. In this work a commercial TO software, SolidThinking Inspire, is used to optimize the geometry of polymeric beams subjected to a three-point bending test under different loading levels. Two different AM technologies are considered to produce the beams: powder bed Selective Laser Sintering (SLS) and material extrusion 3D Printing. Several polymeric materials are used and for the specific AM process the TO calculations are defined by considering the mechanical properties declared by the supplier on the material datasheet. The results of TO are then validated by fabricating and testing replicas of the optimized beams with the corresponding material and process. Starting from the CAD model of a three-point bending beam with some design space for TO, the TO is then executed with different load levels for the different materials and the optimized beam is then fabricated using the corresponding AM process. Finally, the results of the three-point bending test performed on the replicas of the optimized beams are compared to the TO results. Correlation and differences between the experimental behaviour of the beam and the flexural resistance predicted by TO are analysed and discussed

An Overview of the Recent Developments in Metal Matrix Nanocomposites Reinforced by Graphene

Two-dimensional graphene plateletes with unique mechanical, electrical and thermo-physical properties could attract more attention for their employed as reinforcements in the production of new metal matrix nanocomposites (MMNCs), due to superior characteristics, such as being lightweight, high strength and high performance. Over the last years, due to the rapid advances of nanotechnology, increasing demand for the development of advanced MMNCs for various applications, such as structural engineering and functional device applications, has been generated. The purpose of this work is to review recent research into the development in the powder-based production, property characterization and application of magnesium, aluminum, copper, nickel, titanium and iron matrix nanocomposites reinforced with graphene. These include a comparison between the properties of graphene and another well-known carbonaceous reinforcement (carbon nanotube), following by powder-based processing strategies of MMNCs above, their mechanical and tribological properties and their electrical and thermal conductivities. The effects of graphene distribution in the metal matrices and the types of interfacial bonding are also discussed. Fundamentals and the structure–property relationship of such novel nanocomposites have also been discussed and reported

An Overview of Metal Matrix Nanocomposites Reinforced with Graphene Nanoplatelets; Mechanical, Electrical and Thermophysical Properties

Two-dimensional graphene nanoplatelets with unique electrical, mechanical and thermophysical characteristics are considered as an interesting reinforcement to develop new lightweight, high-strength, and high-performance metal matrix nanocomposites. On the other hand, by the rapid progress of technology in recent years, development of advanced materials like new metal matrix nanocomposites for structural engineering and functional device applications is a priority for various industries. This article provides an overview of research efforts with an emphasis on the fabrication and characterization of different metal matrix nanocomposites reinforced by graphene nanoplatelets (GNPs). Particular attention is devoted to find the role of GNPs on the final electrical and thermal conductivity, the coefficient of thermal expansion, and mechanical responses of aluminum, magnesium and copper matrix nanocomposites. In sum, this review pays specific attention to the structure-property relationship of these novel nanocomposites

New Nanocomposite Materials with Improved Mechanical Strength and Tailored Coefficient of Thermal Expansion for Electro-Packaging Applications

In this research, copper nanocomposites reinforced by graphene nanoplatelets (GNPs) were fabricated using a wet mixing method followed by a classical powder metallurgy route. In order to find the best dispersion technique, ball milling and wet mixing were chosen. Qualitative evaluation of the structure of the graphene after mixing indicated that the wet mixing is an appropriate technique to disperse the GNPs. Thereafter, the influence of graphene content on microstructure, density, hardness, elastic modulus, and thermal expansion coefficient of composites was investigated. It was shown that by increasing the graphene content the aggregation of graphene is more obvious and, thus, these agglomerates affect the final properties adversely. In comparison with the unreinforced Cu, Cu–GNP composites were lighter, and their hardness and Young’s modulus were higher as a consequence of graphene addition. According to the microstructural observation of pure copper and its composites after sintering, it was concluded that grain refinement is the main mechanism of strengthening in this research. Apart from the mechanical characteristics, the coefficient of thermal expansion of composites decreased remarkably and the combination of this feature with appropriate mechanical properties can make them a promising candidate for use in electronic packaging applications

Evaluation of a Laboratory-Scale Gas-Atomized AlSi10Mg Powder and a Commercial-Grade Counterpart for Laser Powder Bed Fusion Processing

Laser powder bed fusion (LPBF) is an additive manufacturing technology that implies using metal powder as a raw material. The powders suitable for this kind of technology must respect some specific characteristics. Controlled gas atomization and post-processing operations can strongly affect the final properties of the powders, and, as a consequence, the characteristics of the bulk components. In fact, a complete characterization of the powders is mandatory to fully determine their properties. Beyond the most used tests, such as the volume particle size distribution (PSD) and flowability, the PSD number, the Hausner ratio and the oxidation level can give additional information otherwise not detectable. The present work concerns the complete characterization of two AlSi10Mg powders: a commercial-grade gas atomized powder and a laboratory-scale gas atomized counterpart. The laboratory-scale gas atomization allows to better manage the amount of the fine particles and the oxidation level. As a consequence, a higher particle packing can be reached with an increase in the final density and tensile strength of the LPBF bulk samples

An Overview of Key Challenges in the Fabrication of Metal Matrix Nanocomposites Reinforced by Graphene Nanoplatelets

This article provides an overview of research efforts with an emphasis on the fabrication of metal matrix nanocomposites (MMNCs) reinforced by graphene nanoplatelets (GNPs). Particular attention is devoted to finding the challenges in the production of MMNCs through the powder metallurgy techniques. The main technical challenges can be listed as: (I) reinforcement selection; (II) dispersion of reinforcement within the matrix; (III) reactivity between the reinforcement and matrix; (IV) interfacial bonding; (V) preferred orientation of reinforcement. It is found that some of these difficulties can be attributed to the nature of the materials involved, while the others are related to the preparation routes. It is reported that the challenges related to the process can often be addressed by changing the production process or by using post-processing techniques. More challenging issues instead are related to the composition of the matrix and reinforcement, their reactivity and the dispersion of reinforcement. These topics still bring significant challenges to the materials scientists, and it would be worth mentioning that the fabrication of MMNCs with a uniform dispersion of reinforcement, strong interfacial bonding, without detrimental reactions and improved isotropic properties is still a puzzling issu

Research Progress on Homogeneous Fabrication of Large-Area Perovskite Films by Spray Coating

The bottleneck for large-scale processing within perovskite solar cells (PSCs) development is the stringent need for uniform thin films. On a lab scale, the spin coating methodology with acceptable uncertainty ensures a high level of uniformity with minimal roughness, no voids, and reproducible procedures. However, the technique is strongly limited for up-scaling because the uncertainty is out of range from the spin center to the edge, resulting in areas only up to a few cm2. In order to boost the industrialization of PSCs, the spray coating (SC) methodology can represent a good solution for achieving the goal of uniformity (in terms of crystal size, film thickness, and roughness) that, combined to a reduced active materials waste, compatible to roll2roll production line, will pave the way to PSCs mass production. In this critical review, we present the technological features of SC relevant to PSCs development and critically discuss the key points on which to address the focus for achieving optimal and reliable performances in connection with the fundamental higher potential of SC over spin-coating in allowing to control thin film homogeneity. This review can help in the commercialization of perovskite solar cells but also can contribute to the development of scale-up methodologies